You certainly can use a dashboard for each room if you like. No problem. I've been thinking of going that route too. But for other use cases like Ryan states, it may be better to group devices into a page by function (such as weather, battery condition, motion, etc). The great think here is it's completely up to you.
One thing I'm looking at at the moment, is having an image of my property plan as a background image with a large grid size and then laying motion sensors over the top in their approximate position. So it's a kinda room-based view. It's looking like a really nice panel already (this is just a test mock-up)...
So there are many cool ways to use dashboards. Try this link to get some good ideas...
